Method of preserving fruit and vegetable juices



Patented Dec. 26, 1944 METHOD OF PRESERVING FRUIT AND VEGETABLE JUICESNathaniel M. H. Blumenkranz, Peekskill, N. Y.

No Drawing. Application February 14, 1940,

I Serial No, 318,830

3 Claims.

This invention relates to the preservation of fruit and vegetable juicesand is a continuation in part of my copending application Serial No.286.563, filed July 26, 1939.

The object of the invention is to provide a new and improved method oftreating fruit and vegetable juices to preserve their natural flavor,aroma, and homogeneous qualities while restraining deleterious changesin the juice structure resulting in rancidity or flatness" of the juice.

It is well known that fruit and vegetable juices, such as citrus fruitjuices, apple juice, pineapple juice, tomato juice, carrot juice, etc.,are unstable and rapidly become flat or rancid, particularly whenexposed to light; and many juices such as citrus fruit juices rapidlyseparate or stratify into an upper water layer and a lower concentratedlayer even after the juice is passed through fine screens to removesolid matter therefrom.

Numerous attempts have been made to preserve fruit and vegetable juicesin their natural state, or at least to retard their deterioration aslong as possible, as by packaging the juices in special containersdesigned to exclude all light or certain light rays thought to beinjurious, as well as by special systems of daily deliveries of fruitand vegetable juices to consumers with a view to insuring freshness ofsupply; but all such attempts to preserve the natural flavor, aroma andbody of freshly extracted juices have failed, as is evidenced by thewell known fact that all canned or bottled pineapple juice, orangejuice, grapefruit juice, tomato juice, etc. taste entirely differentfrom the freshly extracted product.

I have now discovered that the deleterious effects of light rays uponfruit and vegetable juices is instantaneous, or practically so, and thatonce the juice is exposed to ordinary light, certain chemical changesare initiated which cause rapid deterioration in spite of anyprecautionary measures which are subsequently taken to package orotherwise preserve the juice in its light and then placing it in arefrigerator or any other darkened enclosure overnight; even though thejuice, so extracted in the daylight, is instantly placed in the darkenedenclosure, it will be found after removal in the morning that the juicehas stratified and very noticeably deteriorated in flavor and aroma. Thesame test can readily be made with other fruit and vegetable juices,with similar results. However, I discovered, first by experimenting withcitrus fruit juices and later with various other fruit and vegetablejuices, that if the juice is extracted from the fruits or vegetables incomplete darkness, or in the presence of light waves longer than 4900Angstrom units while excluding light waves shorter than 4900 Angstromunits, and stored in containers which exclude light waves below 4900Angstrom units, the juice will retain its natural flavor,

. aroma and body for indefinite periods of time.

natural state. In other words, whereas it has heretofore been thoughtthat fruit and vegetable juices were damaged by protracted periods ofexposure to light, and that the longer the exposure the greater thedamage, I have discovered that the damaging effect of light upon fruitand vegetables is practically instantaneous and that even a momentaryexposure to light is suflicient to spoilthe juice and cause it to becomeflat and lose its aroma.

This can easily be demonstrated, for example by extracting the juice ofan orange in the day- Upon making the foregoing discovery I sought todetermine whether the extraction of the juices from the produce in thepresence of light rays above 4900 Angstrom units of the spectrum wasactually beneficial to the juice, or whether the remarkable retention ofthe natural flavor and aroma of the juice resulted rather from theexclusion of all waves of light below 4900 Angstrom units. I have nowdetermined that the essential feature of my invention is the extractionand packaging of fruit and vegetable juices in the complete absence oflight waves below 4900 Angstrom units, that is, light waves in thegreen,

blue, violet and ultra-violet bands, and that if this condition isrigorously adhered to the extraction and packaging of the juices may beperformed equally well either in complete darkness or in the presence oflight waves in the orange, red and yellow bands which'are of wavelengths above 4900 Angstrom units.

In carrying out my invention it is therefore possible to extract andpackage fruit and vegetable juices in absolute darkness, for example bymeans of an automatic juice extracting machine which is suitablyenclosed and therefore works entirely in the dark; but for most purposesI have found this impractical since it is usually desirable to performthe extracting and packaging operations in the open where they can beobserved and regulated as required, and I therefore prefer to carryingout the invention in a closed room which is illuminated only by lightrays above 4900 Angstrom units, which can be accomplished in anysuitable manner as by using a light filter which excludes all waves oflight below 4900 Angstrom units. Under these .condi tions the juice isextracted and then sealed in cans, opaque-jars or transparent ortranslucent containers which are colored to-exclude light waves below4900 Angstrom units, after which the sealed containers are preferablypasteurized.

As an example of my process, juices are pressed out of oranges or otherfruits or vegetables in an enclosed room or chamber illuminated only bylight waves above 4900 Angstrom units, for exto be consumed. The accessto the juice of light waves below 4900 Angstrom units instantlyactivates the enzymes in the juice which produce the change in flavor,aroma, body, etc., and

ample I have used light waves of 4900 to 8000 Angstrom units andsometimes only in the band of 6000 to 8000 Angstrom units, all withexcellent results. Then, while still excluding all light waves below4900 Angstrom units, the juice is sealed in cans or enclosed in eithersmall or bulk containers, and preferably pasteurized. After beingpasteurized, or as an alternative to pasteurization, the juice may bemaintained at a relatively low temperature, preferably above thefreezing point and below 70 F. for a period of hours or more. Theprincipal advantage of such temperature treatments appears to be thatthey inhibit fermentation.

The preferred method of packaging fruit and vegetable juices extractedin the above manner will depend upon the manner in which the juices areto be marketedand used. For ordinary distribution in retail stores andthe like the juices are preferably sealedin cans which in their verynature exclude all light rays from the contents until opened by theconsumer. However, any container which excludes light waves below 4900Angstrom units is equally suitable for this purpose. In other cases,however, the juices may be stored and shipped in large bulk containerswhich exclude light waves below 4900 Angstrom'units,

and then distributed in any suitable retail containers, ev'en ordinaryglass bottles if it is known that the contents are to be consumedshortly it is this undesirable activation of the enzymes which isprevented by my process.

By reason of my invention, orange juice and other fruit and vegetablejuices may be collected in bulk at the seasons when the various fruitsand vegetables are most plentiful and cheap, and transported as incooled tank cars or bulk containers of smaller size and stored for useat a future time. By using retail tins or other containers colored toexclude light waves below 4900 Angstrom units, orange juice as well asother juices may be handled in the same manner that milk is handledafter it leaves the bottling plant and is transported and delivered tothe consumer,

and this with no deterioration in the flavor, aroma or other naturalproperties of the juice.

The invention claimed is:

l. A method of preserving fruit and vegetable juices which comprisesextracting the juice from the produce while excluding all light from thejuice, and, while continuously excluding all light from the juice,enclosing said juice in a con tainer which excludes all light therefrom.

2. Method of preserving fruit and vegetable juices which comprisesextracting the juice from the produce while excluding from the juice alllight waves below 4900 Angstroms and above 8000 Angstroms, and, whilecontinuously excluding from the juice light waves below 4900 Angstromsand above 8000 Angstroms, enclosing said juice in a container whichexcludes all light waves below 4900 Angstroms.

3. Method of preserving fruit and, vegetable juices which comprisesextracting, the juice from the produce while excluding therefrom alllight waves below 4900 Angstrom units and, while continuously excludingfrom the extracted juice all light waves below 4900 Angstrom units,enclosing said juice in containers which exclude light waves below 4900Angstrom units.

NATHANIEL M. BLUMENKRANZ.

